1. Field of the Invention
The present invention particularly relates to a MOS-type solid-state imaging device, a production method thereof, and a camera provided with the solid-state imaging device.
2. Description of the Related Art
In a solid-state imaging device, such as a CCD and a CMOS, a substrate structure is generally used, wherein an n-type epitaxial layer is stacked on an n-type semiconductor substrate (refer to the Japanese Unexamined Patent Publication No. 6-69483). The substrate structure of stacking an n-type epitaxial layer on an n-type semiconductor substrate is often used in a CCD sensor because a semiconductor substrate is predicated on being an n-type when realizing a vertical overflow drain. In a CMOS sensor, a substrate structure of stacking an n-type epitaxial layer on an n-type semiconductor substrate is used for suppressing blooming at the time of taking a picture of a highly bright object.
When using the above substrate structure, sensor portions are formed by introducing an n-type impurity in the n-type epitaxial layer. The sensor potions are formed to have the largest possible area on a unit pixel. Between the sensor portions, that is, between the respective unit pixels, p-type channel stoppers (pixel isolation p-wells) are formed. Alignment of the sensor portions and the pixel isolation p-wells prevents flowing in and out of signal electrons between adjacent sensor portions, which is significant to prevent mixture of colors.